All you have to do is to:
1. bring up the "books" screen (where the books are lined up below each other),
2. touch "device" on top line of screen
3. touch the book you want to delete for 3-4 seconds until the menu pops up
4. touch "delete from device",
5. then touch the arrow in black circle at bottom right of book cover.
Poof, its gone.
Then bring up the carousel screen and repeat steps 2 & 3 and touch "remove from carosel"
you're right - googled it and the answer is
" Go to your bookcase section on the kindle fire. Hold your finger on the book you want to remove until a little screen pops up. It will say add to favorites or remove from device. Just click remove from device. "